In the prior art, sensing edges for doors were permanently attached to the leading edge of the door. Such methods of attachment included the use of adhesives, nails, screws, rivets or the like. These methods are suitable for the purpose intended; however, they have been shown to be troublesome if and when repair or replacement of the sensing edge is required. Since it is or may become necessary to remove a sensing edge from a door in order to repair or replace it, and since the sensing edge was permanently attached to the door, it was difficult to remove the sensing edge without causing damage to the door or the sensing edge itself.
In response to these problems, the assignee of the present invention developed a fastening device, described in U.S. Pat. No. 5,124,511, to act as an intermediary between the edge of the door and the sensing edge. The fastening device described therein is relatively easily securely fastened to the door edge, reducing cost and installation time. Furthermore, since the sensing edge is securely releasably attached to the fastening device and is readily removable, installation, maintenance, and repair are facilitated, promoting additional savings in time and money.
In one embodiment of the above-mentioned fastening device, the device is securely attached to a door edge by means of a mounting plate having elongated clamping members extending from either side. The clamping members are biased inwardly, thereby forming a fastening device having a trihedral cross-sectional shape wherein the distance between the distal ends of the clamping members is less than the width of the door edge to which the fastening device is attached. When the door edge is inserted between the clamping members, the fastening device firmly grips and is secured to the door.
The particular embodiment of the fastening device described above has been successfully manufactured, marketed and installed. However, it presents a disadvantage in that the width of a door edge varies from door to door. As a result, a fastening device that securely grips one door edge may not securely grip another door having a narrower edge. Alternatively, that same device may not be able to contain a third door having a broader edge.
A series of fastening devices of varying widths may be produced to accommodate this problem. However, this requires a manufacturer to make multiple sizes of the same basic design, resulting in additional production costs. Further, an installer of such devices would also incur additional costs in having to inventory and store the multiple sizes. Moreover, the installer may also have the burden of transporting to a work site substantial lengths of multiple sizes of the fastening device, should the need arise. This can become a very cumbersome and expensive task.
The present invention overcomes many of the disadvantages inherent in the above-described fastening device by providing an improvement of the device in which three or more generally parallel elongated clamping members extend from the mounting plate at spaced locations, and where some or all of the clamping members are detachable. By selectively detaching one or more clamping members, an installer may create at the time of installation a fastening device of the proper width for a range of door edges.
The fastening device of the present invention eliminates or significantly reduces the need for producing and stocking multiple sizes of a fastening device. Consequently, the cost and burden of manufacturing, inventorying, storing and transporting the fastening device are significantly reduced, while the advantages of the aforementioned patented device are maintained.